References for Deuteronomy 15:15

16
But if your servant says to you, "I do not want to leave you," because he loves you and your family and is well off with you,

17
then take an awl and push it through his ear lobe into the door, and he will become your servant for life. Do the same for your maidservant.

18
Do not consider it a hardship to set your servant free, because his service to you these six years has been worth twice as much as that of a hired hand. And the LORD your God will bless you in everything you do.